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On arranging the species in order of antiquity it appears that there has been simplification of the vegetative portions of the plant, in particular in the number of first-order branches in a whorl. It must, however, be noted that this is what one would have expected if the size of the first-order branches remained the same and there were a reduction in the circumference of the segment. The con stancy in size of the first-order branches is an interesting feature. It is suggested that this may be correlated with the fact that in Triploporella Remesi and T. Fraasi, as we know definitely, the first-order branches functioned as sporangia and as such might be expected to be more conservative as regards shape and size than purely vegetative organs.

DIAGNOSIS.

Triploporella ranikotensis, sp. nov.

Thallus probably articulate, segments ovoid to conical, in transverse section circular. The extremities of the segments are rounded. The broader, upper extremity has a large depression; the lower extremity a smaller depression. Average length: 5 mm. Diameter of transverse section at broadest part: 2-2.5 mm. The segments consist of a central axial siphon with closely packed whorls of firstorder branch-siphons. The diameter of the axial siphon at any particular level is approximately one-third the diameter of the segment at that level. The first-order branches occur in whorls of 15-20 and are roughly cylindrical but are somewhat flattened at the sides by contact with one another. The spaces between these branches are filled with calcium carbonate secreted by the plant. There are depressions on the outside which represent the bases of second-order branches which arose, 3-7 in number, from the end of each first-order branch.

Locality.-Sind, India.

Horizon.-Ranikot Beds. Tertiary. (Eocene of Europe).

In conclusion, I take the opportunity of expressing my thanks to Prof. Seward of Cambridge who kindly entrusted to me the carrying out of this investigation and to Mr. Gupta who supplied very useful notes and photographs some of which have been used in this account.

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SEWARD, A. C. (1898)

STEINMANN, G. (1899)

Bd. XI. Heft. 2. "Fossil Plants," Vol. I. Cambridge, 1898.

“Ueber fossile Dasycladaceen vom Cerro Escamela, Mexico." Bot. Zeit. 1899. Heft. VIII.

EXPLANATION OF PLATE.

Triploporella ranikotensis, sp. nov.

(Photos. 1, 3, 4, 5, 6 and 7 by B. B. Gupta. Photo. 2 and drawings 8, 9, 10, 11, 12 by J. Walton.) The original specimens are with the Geoloigcal Survey of India, Calcutta.

1. Photo. of a segment covered with the small depressions which correspond to the bases of the 2nd order branches. X 8.

2. Photo. of a segment, weathered a little deeper than that in fig. 1, showing the ends of the 1st order branches outlined faintly by lighter ridges seen clearly at (b). Above the middle the 2nd order branch depressions are seen in distinct groups (c) corresponding to the underlying 1st order branches. x8.

3. Photo. of a differently shaped segment with much the same type of structure visible as at (c), fig. 2. X 8.

4. Photo, of a segment just above the middle; one of the 1st order branches has not been preserved and is represented by a hole (h). Basal depression, (d). x 8.

5. Photo. of larger end of a segment with a double apical depression. x 8.

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6. Portion of a segment weathered deeper and showing the 1st order branches in section. X 8.

7. Photo of a longitudinal section of a segment median at the top, tangential at the base. X 8.

8. Drawing of a similar but accurately median section. × 16.

9. Drawing of a cross section of a segment in the state of that represented in fig. 6. (a) cavity formed by the non-preservation of three 1st order branches (sporangia ?). × 16.

10. Drawing of segment with tangential slice removed. The whorled arrangement of the 1st order branches is evident.

X 16.

11. Drawing of a portion of segment sliced longitudinally and radially showing rather shorter 1st order branch with basal portions of two 2nd order branches. X 16.

12. Drawing of terminal portion of segment showing different stages of weathering. The region (x) corresponds to the state of weathering in fig. 6, (y) to that in fig. 2, and (2) to that in fig. 1. X 16.

220

Records of the Geological Survey of India.

[VOL. LVI.

FROTH FLOTATION OF INDIAN COALS. BY W.
RANDALL, M.SC.

INTRODUCTION.

THE

HE cleaning of coal by froth flotation is a development of the processes known to, and extensively used by, the metalliferous mining industry for some years. It has been successfully applied on a large scale in several countries. During the past two years many of the coals of India have been examined and I am now able to give an indication of the possibilities of applying froth flotation to the treatment of Indian coals.

The advisability of cleaning a coal depends upon the resultant balance between the value of the advantages to be gained by cleaning, and the cost of treatment. The fact that Indian coals have not yet been cleaned on a commercial scale is due, therefore, to one or more of the following reasons :—

(a) The coals are of sufficiently high grade for the purposes for which they are used.

(b) The nature of the coals does not allow of a useful amount of cleaning being done.

(c) The coals are cleanable, but the processes available hitherto have been found to be incapable of treating them successfully on a commercial scale.

Regarding (a), general interest in froth flotation is evidence that the development of a process for cleaning Indian coals is desirable. For special purposes, particularly those of the metallurgical industries, there is a demand for high class coals. The supplies of these are not unlimited, and unless coals of lower grades can be cleaned the present indiscriminate use of the unknown reserves of high grade coals is a serious matter. In addition to work on this very important aspect of coal-cleaning, attention has also been given to the possibility of improving the quality of what are now regarded as first class coals.

Referring to (b), it is widely known that a large proportion of the ash of most Indian coals is inherent or occurs as part of the coal

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substance. Some of the coals are practically homogeneous and are therefore not cleanable by any physical process.

On the other hand, many of the Indian coals are heterogeneous; and in these cases (c), the advisability of cleaning depends on the result of a balance between advantages and costs. The former are determined by the purposes for which the coal is suitable, and by the extent to which it can be cleaned in practice. These factors depend fundamentally on the constitution of the coal.

In testing samples of coal from various sources it has been found that the constitution of a parcel varies with the following factors :

(a) Its origin, i.e. the field, district, and seam.

(b) Whether it is representative of the whole or only part of the seam.

(c) Whether it is "run-of-mine," or a "screen" product.

(d) Whether it has been picked or washed.

Hence the history of any sample submitted for tests is very important. Attention has been given only to samples taken by responsible persons. Samples of run-of mine coal have been obtained directly from working faces. Data concerning the sections and the rejection of shale or other bands have been noted. Samples of screen products have been obtained by special tests on tramloads of coal cut as samples from the coal faces.

CONSTITUTION OF INDIAN COALS.

Most of the Indian coals occur in thick seams, and the proportion of shale bands in the seams is usually very small. The shale bands found in the seams are rarely less than 2 inches in thickness and are therefore easily pickable. Hence the proportion of the ash of picked run-of-mine coal due to shale is in most cases negligible. The bulk of the ash is due to the inferior constituents of the coal itself.

M. Stopes 1 in an important paper, has described the constituents of the bituminous coal of Hamstead Colliery, near Birmingham, England. The publication of this paper did much in directing research on coal towards the investigation of its constituents rather

On the Four Visible Ingredients in Banded Bituminous Coal. Studies in the Composition of Coal, No. 1. Dr. Marie Stopes. Proc. Roy. Soc. Lond., Series B, Vol. XC, p. 470.

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